Oil composition containing arylated metallo-organic inhibitors



Patented Dec. 5, 1939 UNITED STATES OIL COMPOSITION CONTAINING ARYLATEDLlETALLO-ORGANIC INHIBITORS Raphael Rosen, Cranford, N. J., asslgnor toStandard Oil Development Company, a corporation of Delaware No Drawing.Application March 19, 1935, Serial No. 11,811

14 Claims.

The present invention relates to improved oil compositions and moreparticularly to improved mineral lubricating oils and greases containingmetallo-organic compounds.

Oils used for the lubrication of internal combustion engines and forother services involving exposure to high temperatures and air orcombustion gases are subjected to severe oxidizing conditions. The useof metallo-organic com- 9 pounds for the purpose of improvinglubricating oils, including increasing the resistance of such oils tooxidation and for decreasing the amount of carbon and of sludge and thedevelopment of color therein during storage and use, has been suggestedin my pending applications Serial No. 719,603 filed April 7, 1934, andSerial No. 735,202 filed July 14, 1934, issued March 29, 1938 as PatentNo. 2,112,305. The present application is a continuation in part ofthese applications.

It is an object of this invention to improve lubricating compositionsand mineral oil compositions generally by the addition thereto ofarylated metallo-organic compounds of improved solubility in such oils.Other and further objects of this invention will be apparent from thefollowing description and the claims.

A metallo-organic compound is one in which a metallic element isattached directly to at least one carbon atom of a hydrocarbon radical,which radical contains hydrogen also attached to carbon but may inaddition contain other elements such as nitrogen, oxygen, sulfur,chlorine, and the like; or in general may contain various non-metallicelements in addition to hydrogen and carbon.

85 The present invention relates to solubilized aryl metallo-organiccompounds; that is, to metalloorganic compounds in which the metallicelement is connected to a carbon atom of an aromatic hydrocarbon radicalas defined above, and in which the metallic element is also connecteddirectly with a carbon atom of an alkylated aromatic or an aliphatichydrocarbon radical as defined above, and/or with a negative radical.Suitable negative radicals include chlorine, bromine, iodine, sulfur,polysulfide radicals, hydroxyl, SH (hydrosulfide) SCN (thiocyanate), NCS(isothiocyanate), NH2 (amine) and substituted amines, CONHz (amide), N03(nitrate), and the m carboxylic and thiocarboxylic acid radicals.particularly fatty acid radicals such as CH3 COO (acetate), CH3 COS(thioacetate) and the like. One or more valences of the metal may alsobe attached to other hydrocarbon radicals which I may be similar to ordifferent from each other,

' or such valences may be attached to hydrogen atoms or to othernon-metallic atoms.

It has been found that aromatic or aryl groups are far more effectivethan aliphatic or alkyl groups in metallo-organic compounds for improv-5 ing the stability of lubricating oils. However, metallo-organiccompounds containing only aryl groups as the organic component are ofsuch low solubility in hydrocarbon oils, particularly in minerallubricating oils of high quality and visl0 cosity index, that suflicientconcentrations to permit the full improving eifect of such compoundscannot be secured.

It has also been found that the solubility of such completely arylatedmetallo-organic com- 16 pounds can be greatly increased by substitutingan alkyl group or a negative radical for one or more of the aryl groups.The resulting compounds have the desirable characteristics of highefiectiveness in improving lubricating oils and of sufli- 20 cientsolubility for the preparation of optimum concentrations, and arepreferred according to the present invention.

'Examples of metallo-organic compounds suitable for the presentinvention are: 26

In addition to increasing the solubility in oil of the arylatedcompounds, the substitution of negative radicals also in many instancesproduces metallo-organic compounds of increased eflectiveness. Forexample, the iodide and sulfide radicals possess this power to a markeddegree;

aryl metallo-organic iodides and aryl metalloorganic sulfides beinghighly eflective lubricating oil sludge preventers and stabilizers.

' znegativeradicalslto he substitutedior-aryi groups ior.best',resuitsdepends upon the nature :ofathe number and-type of groups anti/or arylgroups. In metailo-organic compounds con- "taining relatively simplearyl groups, such as ing as many as the solubility characteristics otthe compound will permit. With complex aryl groups having a condensedring structure, such as naphthyls, anthracyls, etc., it may be necessaryto replace two or more such groups with solubilizing groups for bestresults.

The nature of (the solubilizing groups also varies. Alkyl groups having10 to 18 carbon atoms in a straight chain have a greater solubilizingeffect than alkyl groups of 2 to 6 or 8 carbon atoms. The alkyl groupsmay be either of straight or branched chain'structure, including normal,iso, secondary, tertiary and/or cyclo allwl groups, such as isopropylgroups, secondary butyl groups, tertiary amyl groups and cycle hexylgroups, also cyclo naphthenic groups, and alkylated aromatic groups suchas benzyl, cresyl, propyl-phenyl, butyl-cresyl, octyl-phenyl, and thelike. V

Alkylation of one or more of the aryl groups of the metallo-organiccompound also increases its solubility. For example, metallo organiccompounds may be used having cresyl groups, propylphenyl groups,butyl-phenyl groups, or other aryl groups containing one or more alkylgroups, of 1 to 6 or more carbon atoms, which may be normal, iso,secondary, tertiary and/or cyclo alkyl groups, attached to a carbon atomof the aryl ring.

The organic radicals, both aryl and alkyl, need not be purelyhydrocarbon radicals although it is generally so preferred. For example,they may contain hydroxy and amino groups, and/or halogen or sulphur orother elements, and of particular importance are the hydroxy and aminoderivatives of the aryl compounds.

While the exact nature of these various compounds and the mechanisms bywhich they improve the oils to which they are added, are notparticularly understood, it is observed that all appear to show to agreater or lesser degree the property of decreasing the sludgingtendency of the oil, which means that such decomposition products as areformed under their influence whatever their nature, are, for the mostpart, freely soluble or, at least, dispersable in the oil,

and that the tendency towards precipitation is thus greatly diminished.This improvement in lubricating oils is described generally as areduction in sludge formation.

The compounds used for the present compositions are those which aresoluble in hydrocarbon oils, at least to the extent necessary for theindicated purposes. If a particular eompoimd is found not to besufficient y soluble for the best results, it has been found that theaddition of more alkyl groups or of allryl groups containing a greaternumber of carbon atoms will increase the solubility to the pointdesired. It is often desirable to add small amounts of benzol or toluolor their equivalents to dissolve the compounds to be added, and to causetheir intimate dispersion through the oil. If desired, the lowermolecular weight solvents may be removed by distillation or otherwise,in order to obtain lubriass sts stating-compositions of desiredvolatility, flash, -e c.

' The amount of the metallo-organic compound used may be very small; forexample, as little as 0.01 to 0.02% often produces substantiallybeneficial results, but it is generally desirable to use about 0.05% to0.2% of these compounds,

and it is rare that more than 0.5% is required waxes or greases. Thesemetallo-organic compounds may be used with such lubricating com- Ipositions derived from all varieties of crudes including paraflinic,naphthenic and the various mixed base crudes. The lubricatingcompositions used may be obtained and refined by the ordinary methods ofdistillation, acid treating, clay treating, alkali treating, andcombinations of such treating operations, solvent extraction,bydrogenation, destructive hydrogenation, and the like, including thetreatments with excess of strong or fuming sulfuric acid to produce thehighly refined whi oils which are used for medicinal and technicalpurposes. These compounds are of particular value in motor oils,especially for crankcase lubrication, flushing oils, turbine oils,transformer oils, top cylinder lubricants, cable oils, switch oils,greases, and other lubricants used for similar purposes. The lubricantsmay contain more than one of the particular metallo-organic compoundsmentioned herein, or all of these compounds in admixture with othermetallo-organic compounds, and may also contain other substances whichare customarily added to lubricating oils, such as pour pointdepressors, oiliness agents, dyes for cast and color, extreme pressureagents, thickeners, sludge dispersers and the like. The addition ofoxidation inhibitors, such as p-naphthol and sulfurized phenol, is alsoof advantage as' these serve to a solubilizing group has beensubstituted for one of the aryl groups.

Example 1 Tetraphenyl lead, triphenyl lead iodide, tetraphenyl tin,triphenyl tin iodide and triphenyl tin chloride were each dissolved inseparate portions of a petroleum lubricating oil prepared from a Gulfcrude, and a petroleum lubricating oil prepared by hydrogenation of aColombia crude.

The Gulf oil was of 15 V. I. and is a much better solvent for aromaticcompounds generally than is the hydrogenated oil. The solutions wereprepared by warming the oil, with stirring, until the metallo-organiccompounds were completely dissolved. The solutions were then cooled toroom temperature and then to 5 C. Solutions containing both 0.1% and0.2% by weight of triphenyl lead iodide, triphenyl tin iodide andtriphenyl tin ch oride showed no precipitation at either roomtemperature or 5 C. All solutions containing 0.2% of tetraphenyl leadand tetraphenyl tin formed precipitates at both room temperature and 5C. Solutions containing 0.1%

of tetraphenyl lead and tetraphenyl tin formed precipitates from thehydrogenated oil at 5 C. but did not form precipitates from the Gulf oilat 5 C. or from either the hydrogenated oil or the Gulf oil at roomtemperature.

Erample 2 Example 3 A blank sample of a highly refined lubricating oil,S. A. E. 50, prepared by hydrogenation, was compared in a series oftests with samples of the same oil to which were added varying amountsof metallo-organic tin compounds of the types and in the concentrationsshown in the following table:

Percent Cone Oxygen ab- Sligh humor 2223? test sorption test test Blankoil (Hyd. S. A. E.

0. 50 103-213-107 5 Triphenyl silicon hydride 0. 2 0. 42 'lriphenylbenzyl ger' manium 0. 2 0. 39 Phenyl tribenzyl tin..- 0.2 0. 18Triphenyl tin sulfide" 0. 2 0. 08 3-3-3-6 40. 7 'lriphenyl n-butyl tin 20. 2 0. l5 5-8-7-8 'lri--naphthyl ethyl tin. 0. 2 0. l4 Triphenyl tiniodide 0. 2 0. 03 6-10-12-12 3. 4 Do 0. 05 0. 2i 21-17-l4l7 3. 3'lriphenyl tin chloride". 0. 2 0. l4 6-6-9-6 40. 6 Triphenyl tin bromide0. 2 0. 20 7-7-7-8 Do 0. 05 0. 27 Di henyl tin di-iodido... 0. 05 0. 2923-2522l7 6. 9 Trflihenyl tin hydroxide. 0. 20 0. l1 Do 0. 05 0. 2228-12-8-4 l6. 5 Triphenyl tin thiocya- 0.20 0.11 ll-l2l8-9 Triphonyllead iodide.-.. 0. 2 0. 42 Do 0. 05 0. 42 53 58-6l56 Diphenyl arsenicchloride 0. 2 0. 24 7544-36 Emmple 4 A blank sample of a highly refined,phenol treated lubricating oil, S. A. E. 50, from a Mid-Contb nent crudewas compared in a series of tests with samples of the same oil to whichwere added triphenyl tin iodide in varying concentrations, as

' indicated in the following table:

Concen- Cone Oxygen absorp- Sligh Inmbm tration t tion test test Blankoil 0. 40 44-35-34-26 4. 8 'lriphenyl tin iodide. 0. 2 0. l4 3 4. 1 Do0. 05 0. 25 Do 0. 025 0. 3

either the reactions or the constituents reacting or both, may differfrom those causing sludge formation. It is significant that themetallo-organic tin iodides give low figures for the Sligh test as wellas for the cone test and the oxidation rate test. This has not beenobserved with other metallo-organic tin halides.

The cone test is conducted by passing the oil at a definite rate througha groove cut in the inner surface of a steel cone of standardizeddimensions held at a temperature of 250 C. The figure reported is thedeposite which is the total naphtha insoluble residue deposited on thecone and found suspended in the oil at the end of the test. The figurereported represents milligrams of insolubles per cc. of oil.

The oxygen absorption test represents the amount of oxygen in cubiccentimeters absorbed during successive 15-minute intervals when oxygenis conducted in a closed circuit, bubbling through 10 cc. of the oil,which is maintained at a temperature of 200 C.

The Sligh test is conducted according to the A. S. T. M. procedureexcept that it is conducted for 24 hours instead of the 2-hour periodrecommended. See Proc. American Society for Test Materials24,964-II(1924).

From the above tables it is apparent that the solubilized arylmetallo-organic tin compounds are particularly efiective.

The present invention is not to be limited to any theoreticalexplanation of the action of the metallo-organic compounds, nor to anyparticular compounds, which are disclosed herein solely for purpose ofillustration, but is to be limited by the following claims, in which itis desired to claim all novelty insofar as the prior art permits.

I claim:

1. A composition of matter comprising a hydrocarbon oil of the typeboiling above kerosene, containing in solution a minor proportion of anaryl metallo-organic compound having an alkyl group attached to ametallic element thereof, said alkyl and aryl groups being connected bycarbon atoms to the same atom of said metallic element.

2. A composition according to claim 1 in which said alkyl group is anaryl-alkyl group.

3. A composition according to claim 1 in which said alkyl group is abenzyl group.

4. A composition of matter comprising a hydro-carbon oil of the typeboiling above kerosene containing in solution a minor proportion of ametallo-organic compound having both an aryl group and a negativeinorganic radical connected to the metallic element thereof, said arylgroup being connected by a carbon atom to said metallic element.

5. A composition according to claim 4 in which said inorganic radical isa sulfide.

6. A composition according to claim 4 in which said inorganic radicalcontains sulfur.

7. A composition according to claim 4 in which said inorganic radical isa halide.

8. A composition according to claim 4 in which said inorganic radical isan iodide.

9. A composition according to claim 4 in which said inorganic radical isselected from the group consisting of hydrides and hydroxides.

10. A composition according to claim 4 in which one valence of themetallic element of said metallo-organic compound is connected to theinorganic radical and the remaining valences are connected to arylgroups.

11. A composition according to claim 4 in which one valence oi themetallic element of said metallo-organic compound is connected to theinorganic radical and the remaining valences are 3 connected (to phenylgroupa.

12. A composition of matter comprising a hydrocarbon oil of the typeboiling above kerosene containing in solution a minor proportion of ametailo-organic tin iodide compound having a carbon atom of at least onearomatic hydrocarbon radical. attached directly to the tin.

13. A composition according to claim 12 in which said metallo-organiccompound is a triaryl tin iodide.

14. A composition according to claim 12 in which said metallo-organiccompound is triphenyl tin iodide.

' RAPHAEL ROSEN.

